1. Field of the Invention
This invention relates to pumps used in washing appliances.
2. Description of the Prior Art
Drain pumps and wash pumps are used in washing appliances such as dishwashers. During the operation of a washing appliance air can be introduced into the pump housing. Air can build up to such an extent that liquid priming of the pump may be impeded or even prevented.
A dishwasher drain pump is disclosed in U.S. Pat. No. 6,398,495. The drain pump is designed in a way that allows air trapped in the pump impeller chamber to be bled out of the pump soil pipe. However, the pump design does not allow all trapped air to be bled off, such that a level of air can remain trapped in the impeller chamber. The pump impeller is designed to overcome the level of air that can remain trapped, to allow adequate priming of the pump. While this drain pump operates satisfactorily, the efficiency of the pump can be affected by the level of air that can remain trapped.